RIASSUNTO
ABSTRACT:
This study aims to clarify the characteristics of ice floe run-up through field observation and laboratory experiments. In field observation, run-up height, size and shape of ice floes on sloping beach, and topography of beach were measured. Laboratory experiments were also conducted in order to examine the relation between run-up height, shape of ice and wave condition.
INTRODUCTION
The adjacent sea of northeast coast of Hokkaido island facing the Sea of Okhotsk is covered by ice floes from January to March every year. Ice floes that hit the Sea of Okhotsk coast of Hokkaido play an important role for marine resources by accelerating the increase of plankton and serve as a valuable tourist resource in winter. However, they may cause damage to coastal structures, marine resources such as kelp and scallops and the aquaculture facilities of these resources. Table 1 shows a summary of influences of ice floes on maritime facilities. In the Sea of Okhotsk, for example, when the ice concentration is low, sometimes the sea becomes rough and some of the ice floes are brought onto sloping beach. Due to such ice floe run-up, aquaculture and fishery resources are sometimes damaged. Also shoreline facilities like embankment can be damaged. A large number of ice floes that run up close to the shoreline may also form a bank and expand erosion of coast caused by waves. Although it is necessary to predict the run-up height, size, number and other details of ice floes on the planning and designing of shoreline facilities and aquaculture facilities, there are few precedent studies. This study was conducted in order to clarify the run-up characteristics of ice floes by field observation of ice floe run-up on the beach caused by waves. Laboratory experiments in a water tank were also conducted.